Battery powered devices are becoming increasingly common. In many applications, the size and/or weight of the battery used to power the device is preferably as small as possible with respect to the power required by the device. Additionally, it is preferable that the battery have a long life that accommodates a high number of discharge/charge cycles. For example, because lithium ion (Li-ion) batteries have a high specific energy and have a favorable aging characteristics relative to lead acid batteries and nickel metal hydride batteries, Li-ion batteries are in wide use in portable electronics (e.g., cell phones, portable computers, etc.). The use of Li-ion batteries in electric vehicles is also increasing.
High specific energy batteries, however, may be susceptible to catastrophic thermal runaway. Thermal runaway may be triggered via conditions such as overcharge, over-discharge, and/or internal short circuits, which may cause an internal temperature of the battery to significantly exceed a safe temperature limit. Above a critical temperature, exothermic reactions can occur that cause further temperature increase, which may result in additional exothermic reactions leading to thermal runaway. A thermal runaway can be a significant safety issue. For example, with a Li-ion battery, temperatures as high as 900° C. may occur as well as the release of a substantial amount of flammable and toxic gas.